生物医学工程专业《数字信号处理》课程教学实验的设计

目的根据生物医学工程专业本科教学特点,设计了《数字信号处理》课程的实验教学方法和内容。方法采用Dreamweaver将实验讲义开发成网页形式;利用JAVA设计了4个教学辅助插件,方便地嵌入网页结构中;利用辅助插件对教学中的算法原理进行验证和演示,并使实验内容在Matlab平台下编程实现。结果实验结果证实该实验教学课件有效地提高了生物医学工程专业《数字信号处理》课程教学的效果。     

Image analysis of soft-tissue in-growth and attachment into highly porous alumina ceramic foam metals

The detailed quantitative characterization of soft-tissue in-growth into highly porous artificial implants is critical to understanding the biophysical processes that will lead to the best structural scaffolding construct. Previous studies have performed mechanical peel tests and mostly qualitative histological analyses of soft-tissue. The goal of this paper is to report the results obtained from applying two image analysis algorithms to quantify the morphological structure found in histological images of stained soft-tissue in-growth into alumina ceramic foam metal implants using a canine model. Three different pore sizes were used and three different post-operative time points were considered. Using the 2D Wavelet Transform Modulus Maxima method and 2D Fourier Transform analysis, a strong anisotropic signature (directional preference) is detected in early (4-week) histological samples. The direction of preference is towards the center of the implants. The strength of the anisotropy at later time points (8 and 16 weeks) becomes gradually weaker. Our interpretation is that after a short period of time, the main tissue growth activity has been concentrated on filling the artificial implant by growing towards its center. The weaker anisotropic signature found at later time points is interpreted as the tissue growth activity strengthening its structure by growing in more random directions.     

跟腱区动脉血供的三维可视化研究

目的通过数字化技术构建跟腱区动脉血供的三维可视化图像,研究跟腱区的动脉血供。方法新鲜人小腿标本三只,用30％明胶、10％朱砂、10％淀粉按比例配制的灌注液灌注,冷藏后CT扫描获得DICOM格式数据,Mimics 10．01软件处理。结果获得小腿跟腱区皮肤、骨骼、动脉、跟腱的三维可视化图像。结论跟腱区三维可视化图像可为临床提供形态学资料,虚拟手术有助于最佳手术方案的选择。     

37例肺小腺癌的64层螺旋CT扫描征象分析

目的探讨64层螺旋CT对肺小腺癌的诊断价值。方法回顾37例行64层螺旋CT薄层容积扫描,利用副台分别行多平面重组(MPR)、最大密度投影(MIP)、最小密度投影(MinIP)重建的CT影像特征及病理结果,对其征象进行分析。结果37例中,见分叶征33例,小泡征19例,空气支气管征15例,毛刺征30例,血管集束征27例,胸膜凹陷征24例,磨玻璃样密度3例。结论64层螺旋CT薄层扫描及后处理图像对小腺癌诊断具有很大价值。小腺癌结节内细支气管气像对诊断具有一定意义。     

Co‐speech gestures influence neural activity in brain regions associated with processing semantic information

Everyday communication is accompanied by visual information from several sources, including co‐speech gestures, which provide semantic information listeners use to help disambiguate the speaker's message. Using fMRI, we examined how gestures influence neural activity in brain regions associated with processing semantic information. The BOLD response was recorded while participants listened to stories under three audiovisual conditions and one auditory‐only (speech alone) condition. In the first audiovisual condition, the storyteller produced gestures that naturally accompany speech. In the second, the storyteller made semantically unrelated hand movements. In the third, the storyteller kept her hands still. In addition to inferior parietal and posterior superior and middle temporal regions, bilateral posterior superior temporal sulcus and left anterior inferior frontal gyrus responded more strongly to speech when it was further accompanied by gesture, regardless of the semantic relation to speech. However, the right inferior frontal gyrus was sensitive to the semantic import of the hand movements, demonstrating more activity when hand movements were semantically unrelated to the accompanying speech. These findings show that perceiving hand movements during speech modulates the distributed pattern of neural activation involved in both biological motion perception and discourse comprehension, suggesting listeners attempt to find meaning, not only in the words speakers produce, but also in the hand movements that accompany speech. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.     

Processing of facial affect under social threat in socially anxious adults: mood matters

Background: An important function of the human face is to communicate approval or disapproval toward others. Because socially anxious individuals are overly concerned about disapproval by others, it has been hypothesized that those individuals are faster at processing negative, specifically angry facial expressions than nonanxious individuals, especially under conditions of social threat. Method: To test this hypothesis, 25 socially anxious individuals and 24 nonanxious controls were asked to classify facial expressions associated with anger, sadness, fear, disgust, happiness, and surprise. Half of the participants performed this task while being confronted with social threat. Results: High socially anxious participants were faster than controls at classifying angry, sad, and fearful faces when confronted with social threat. No group difference was observed under the no‐threat condition. Conclusions: The findings suggest that socially anxious individuals are more hypervigilant toward threat‐related social cues, and that the processing of facial affect is dependent on the person's emotional state. Depression and Anxiety, 2009. © 2008 Wiley‐Liss, Inc.     

Enhancing the validity and utility of randomized clinical trials in addictions treatment research: III. Data processing and statistical analysis

PURPOSE: This is the third paper in a series that reviews strategies for optimizing the validity and utility of randomized clinical trials (RCTs) in addictions treatment research. Whereas the two previous papers focused on design and implementation, here we address issues pertaining to data processing and statistical analysis. SCOPE: Recommendations for enhancing data quality and utility are offered in sections on data coding and entry; and data format, structure and management. We discuss the need for preliminary data analyses that examine statistical power; patterns of attrition; between-group equivalence; and treatment integrity and discriminability. We discuss tests of treatment efficacy, as well as ancillary analyses aimed at explicating treatment processes. CONCLUSIONS: Safeguards are necessary to protect data quality, and advance planning is needed to ensure that data formats are compatible with statistical objectives. In addition to treatment efficacy, statistical analyses should evaluate study internal and external validity, and investigate the change mechanisms that underlie treatment effects.     

Visual system of calliphorid flies: motion- and orientation-sensitive visual interneurons supplying dorsal optic glomeruli

Intracellular recordings accompanied by dye fills were made from neurons associated with optic glomeruli in the lateral protocerebrum of the brain of the blowfly Phaenicia sericata. The present account describes the morphology of these cells and their electrophysiological responses to oriented bar motion. The most dorsal glomeruli are each supplied by retinotopic efferent neurons that have restricted dendritic fields in the lobula and lobula plate of the optic lobes. Each of these lobula complex cells represents a morphologically identified type of neuron arranged as an ensemble that subtends the entire monocular visual field. Of the four recorded and filled efferent types, three were broadly tuned to the orientation of bar stimuli. At the level of optic glomeruli a relay neuron extending centrally from optic foci and a local interneuron that arborizes among glomeruli showed narrow tuning to oriented bar motion. The present results are discussed with respect to the behavioral significance of oriented motion discrimination by flies and other insects, and with respect to neuroanatomical data demonstrating the organization of deep visual neuropils.     

Atypical Categorical Perception in Autism: Autonomy of Discrimination?

A diminished top-down influence has been proposed in autism, to account for enhanced performance in low-level perceptual tasks. Applied to perceptual categorization, this hypothesis predicts a diminished influence of category on discrimination. In order to test this hypothesis, we compared categorical perception in 16 individuals with and 16 individuals without high-functioning autism. While participants with and without autism displayed a typical classification curve, there was no facilitation of discrimination near the category boundary in the autism group. The absence of influence of categorical knowledge on discrimination suggests an increased autonomy of low-level perceptual processes in autism, in the form of a reduced top-down influence from categories toward discrimination.